Safety-type wire joints material:Nylon66,94-2agree,by UL. Safety-type wire jointsmaterial:Nylon66,94-2agree,by UL.Usage:peel the coat of wire,then insert to tube ,use pincers to fix them, Inside material:made of Steel tube T1,the surface is silver-gilt.Feature:Nylon shell,long copper tube,easy to conduct electricity and hold wire tight.